(a) Technical Field
The present invention relates to a probe and a device for detecting abnormality of an intervertebral disc. More particularly, the present invention relates to a probe and a device for detecting abnormality of an intervertebral disc that gives vibration stimulation to the inner part of the intervertebral disc and obtains an ultrasonic image in order to sense the abnormality of the intervertebral disc causing discogenic pains and inspects whether the intervertebral disc is abnormal by measuring the impedance in the intervertebral disc.
(b) Background Art
Low back pain or neck pain has been known as the next most common symptom to a cold with a probability that a person will suffer from the low back pain or neck pain at least once during life time is approximately 30%. Major factors causing the low back pain or neck pain may include lumbar arthralgia, spinal-pelvic arthralgia, discogenic pain, and disc herniation. Among them, disc herniation, commonly known as ‘disc’ is a disorder in which an intervertebral disc protrudes causing low back pain or neck pain and a nervous symptom. However, damages of a disc are more common etiology of pains than disc herniation.
Referring to FIG. 1, FIG. 1(a) shows the normal intervertebral disc, FIG. 1(b) shows a degeneratively changed intervertebral disc, and FIG. 1(c) shows an intervertebral disc in which a laceration is generated in annulus fibrosus. In the normal intervertebral disc 1, a sinu-vertebral nerve 3 is distributed along the edge of the annulus fibrosus 5. However, as the intervertebral disc is degeneratively changed, a sinu-vertebral nerve 3 is extended and distributed to the inside of the annulus fibrosus 5 and when the laceration 7 of the annulus fibrosus is generated in the annulus fibrosus 5, the sinu-vertebral nerve 3 is extended up to nucleus pulposus to cause an acute pain.
In recent years, the most accurate method for inspecting the intervertebral disc is known as magnetic resonance imaging (MRI). However, when a waist MRI was performed on normal persons with no low back pain or neck pain previously known, it was found that approximately 70% of them had abnormalities in the intervertebral disc. This fact indicates that the abnormalities of the intervertebral disc do not always lead to low back pain or neck pain. Further, it is still unclear whether the abnormalities discovered in the intervertebral disc from MRI performed on the patients with definite low back pain or neck pain are the main causes of such pain.
As a method of detecting the abnormality of the intervertebral disc, the intervertebral disc discography is a traditional technique that was first practiced in 1948. Even though its inherent technical value has been diminished over time, it has been proven to be effective as a modality to perform disc stimulation recently. In recent years, the intervertebral disc discography involves injecting a contrast material into the intervertebral disc and utilizes a graphical image to diagnose whether the intervertebral disc is abnormal. It can also be used to verify whether the abnormality of the intervertebral disc is the main cause of the low back pain or neck pain by observing patients feeling certain pains when the contrast medium is injected.
The inspection process of the discography will be described below in brief.
First, the patient lays face down on a bed and a waist of the patient is disinfected and thereafter, a needle (e.g., a diameter in the range of 22 to 25 gauge and a length of 5 inch) for injection is pierced obliquely (approximately at 45 degrees) while viewing a radioscope and the end of the needle is positioned at the center of the intervertebral disc.
Next, a syringe is filled with a constant material (displayed white in the radioscope because the contrast material is opaque to radiation) and connected to the needle for injection which is already inserted.
The contrast material diffused in the intervertebral disc is observed by using the radioscope while the contrast material is slowly injected to verify whether the patient complaints of pain. When the internal pressure of the intervertebral disc increases while the contrast material is filled in the intervertebral disc, a pain sensory nerve distributed in the intervertebral disc is stimulated, causing pain. When the same degree of low back pain or neck pain as the general low back pain or neck pain is caused during inspection, an inspection result is judged as positive and the inspected intervertebral disc is identified as the cause of the low back pain or neck pain.
The inner part of the intervertebral disc which is referred to as nucleus pulposusis primarily made of proteoglycan and collagen and contains moisture. Nucleus pulposus may be in a semi-solid state. Since the contrast material which is in a liquid state is injected in vertebral pulp, it takes time to evenly diffuse the contrast material. Accordingly, when an injection speed of the contrast material increases, higher pressure than general pressure is formed and when the injection speed of the contrast material decreases, lower pressure than the general pressure is formed. In this case, when the same degree of low back pain or neck pain as the general low back pain or neck pain is caused during inspection, an inspection result is judged as positive and the inspected intervertebral disc is identified as the cause of the low back pain or neck pain.
Since discography is performed in a manner in which an operator questions a degree of pain to the patient, the inspection can be completely fulfilled only when the pain sensory nerve distributed in the intervertebral disc is stimulated by the increased pressure. When the structure of annulus fibrosus in the intervertebral disc is maintained to some degree, the amount of the contrast material injected into nucleus pulposusis maintained as much, and as a result, the pressure is also increased. Therefore, pain may be caused to diagnose nucleus pulposusis by using the existing discography. However, when the contrast material injected into the intervertebral disc is leaked to the outside due to a severe degenerative change in the intervertebral disc, the increase in the internal pressure of the intervertebral disc cannot be expected, and as a result, stimulation of a nerve extended into the intervertebral disc is also not available, thereby not causing pain. In some cases, the nerve intends to be stimulated by rapidly injecting the contrast material, but a failure probability is high.